Patterns of coal workers' pneumoconiosis in Appalachian former coal miners. (65/300)

To aid in diagnostic chest film interpretation of coal workers' pneumoconiosis, a composite profile of common radiologic patterns was developed in 98 Appalachian former coal miners who were diagnosed as having coal miner's pneumoconiosis and who applied for black lung benefits. The mean age was 61 years, with a lifetime coal mine dust exposure of 18.7 years. Results showed that chest radiographs of coal workers' simple pneumoconiosis contained small irregular linear opacities more frequently (47%) than small rounded opacities. Sparse profusion of all small opacities was the rule. Small opacities involved two out of six lung zones simultaneously 39% of the time while other combinations occurred less frequently. Lower zones were involved more frequently than upper ones. Thickened pleura occurred in 18% of radiographs. Other frequent radiographic abnormalities were parenchymal calcifications (19%), marked emphysema (12%), and inactive tuberculosis (12%). Calcification of the aortic knob, a degenerative process reflecting age, occurred in 9%. Only one instance of complicated coal workers' pneumoconiosis (progressive massive fibrosis) was encountered (0.7%). Many of the descriptive features of coal workers' pneumoconiosis noted in the literature were not observed in this study. Only one instance of complicated pneumoconiosis was encountered.  (+info)

Dendriform pulmonary ossification in patient with rare earth pneumoconiosis. (66/300)

The case history is presented of a patient with pathologically proven dendriform pulmonary ossification and rare earth pneumoconiosis confirmed by analytical transmission electron microscopy. This is thought to be the first report of this association.  (+info)

Mapping and prediction of coal workers' pneumoconiosis with bioavailable iron content in the bituminous coals. (67/300)

Based on the first National Study of Coal Workers' Pneumoconiosis (CWP) and the U.S. Geological Survey database of coal quality, we show that the prevalence of CWP in seven coal mine regions correlates with levels of bioavailable iron (BAI) in the coals from that particular region (correlation coefficient r = 0.94, p < 0.0015). CWP prevalence is also correlated with contents of pyritic sulfur (r = 0.91, p < 0.0048) or total iron (r = 0.85, p < 0.016) but not with coal rank (r = 0.59, p < 0.16) or silica (r = 0.28, p < 0.54). BAI was calculated using our model, taking into account chemical interactions of pyrite, sulfuric acid, calcite, and total iron. That is, iron present in coals can become bioavailable by pyrite oxidation, which produces ferrous sulfate and sulfuric acid. Calcite is the major component in coals that neutralizes the available acid and inhibits iron's bioavailability. Therefore, levels of BAI in the coals are determined by the available amounts of acid after neutralization of calcite and the amount of total iron in the coals. Using the linear fit of CWP prevalence and the calculated BAI in the seven coal mine regions, we have derived and mapped the pneumoconiotic potencies of 7,000 coal samples. Our studies indicate that levels of BAI in the coals may be used to predict coal's toxicity, even before large-scale mining.  (+info)

Surveillance data on US coal miners' pneumoconiosis, 1970 to 1986. (68/300)

OBJECTIVES: Statistics on prevalence of pneumoconiosis among working underground coal miners from data collected as part of a large national radiographic surveillance program between 1970 and 1986 are presented. The main intent was to examine the time-related trend in prevalence over this period, which coincides with historically low dust levels mandated by federal act. METHODS: Tenure-specific prevalence rates and summary statistics derived from them for four consecutive time intervals within the 16-year period were calculated and compared. RESULTS: The results indicate a reduction in pneumoconiosis over the life of the program. This trend is similar to that seen in epidemiologic studies undertaken concurrently. CONCLUSIONS: Although low participation in the surveillance program and other problems complicate the findings, it appears that reductions in dust exposure mandated by federal act in 1969 have led to lower prevalence of pneumoconiosis among underground coal miners.  (+info)

British data on coal miners' pneumoconiosis and relevance to US conditions. (69/300)

OBJECTIVES: The current primary federal dust standard for US underground coal miners of 2 mg/m3 respirable dust is based on British epidemiological information on exposure-response derived in 1969. Since then, much new information has become available. This paper reviews and compares the available information as it relates to the US mining situation. METHODS: Recent exposure-response information on pneumoconiosis and dust exposure derived by British researchers was employed to estimate working-life risks of pneumoconiosis for miners exposed to 2 mg/m3. RESULTS: It is estimated that close to 9% of underground coal miners who work for 40 years in a 2 mg/m3 environment would develop pneumoconiosis (category 1 or greater). Progressive massive fibrosis would develop in 0.7%. CONCLUSIONS: There are unresolved questions relating to the validity of extrapolating findings on British mines and miners to the US and also in predicting disease levels at the low end of the dust exposure spectrum. Given the data available, current information suggests miners who are employed for a working life-time at the current federal dust limit of 2 mg/m3 are still at risk of developing pneumoconiosis.  (+info)

Rapidly progressive coal workers' pneumoconiosis in the United States: geographic clustering and other factors. (70/300)

BACKGROUND: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers' pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue to occur among coal miners. AIMS: To identify US miners with rapidly progressive CWP and to describe their geographic distribution and associated risk factors. METHODS: Radiographic evidence of disease progression was evaluated for underground coal miners examined through US federal chest radiograph surveillance programmes from 1996 to 2002. A case of rapidly progressive CWP was defined as the development of PMF and/or an increase in small opacity profusion greater than one subcategory over five years. County based prevalences were derived for both CWP and rapidly progressive cases. RESULTS: A total of 886 cases of CWP were identified among 29 521 miners examined from 1996 to 2002. Among the subset of 783 miners with CWP for whom progression could be evaluated, 277 (35.4%) were cases of rapidly progressive CWP, including 41 with PMF. Miners with rapidly progressive CWP were younger than miners without rapid progression, were more likely to have worked in smaller mines (<50 employees), and also reported longer mean tenure in jobs involving work at the face of the mine (in contrast to other underground mining jobs), but did not differ with respect to mean underground tenure. There was a clear tendency for the proportion of cases of rapidly progressive CWP to be higher in eastern Kentucky, and western Virginia. CONCLUSIONS: Cases of rapidly progressive CWP can be regarded as sentinel health events, indicating inadequate prevention measures in specific regions. Such events should prompt investigations to identify causal factors and initiate appropriate additional measures to prevent further disease.  (+info)

Health-related quality of life in community-dwelling men with pneumoconiosis. (71/300)

BACKGROUND: There have been few data on the health-related quality of life (HRQOL) in patients with pneumoconiosis. HRQOL is an important aspect of daily living in patients with industrial diseases. OBJECTIVES: To investigate the HRQOL and factors that contribute to the impairment of HRQOL in patients with pneumoconiosis. METHODS: 297 patients with pneumoconiosis were recruited from a community-based case registry. The HRQOL was measured with the St. George's Respiratory Questionnaire (SGRQ). Pulmonary function, comorbidity and psychosocial variables were also assessed. Patients' mood state was evaluated with the Geriatric Depression Scale (GDS). RESULTS: The mean SGRQ symptom, activity, impact and total scores were 38.0 +/- 19.3, 44.5 +/- 21.9, 34.2 +/- 17.9 and 39.4 +/- 17.4, respectively. These figures were lower than those reported in patients with chronic obstructive pulmonary disease who attended chest clinics. The GDS score (r = 0.38), forced expiratory volume in 1 s predicted (FEV(1)% predicted;r = -0.33) and comorbidity (r = 0.21) were the most important predictors of the HRQOL. CONCLUSIONS: Besides lung functions, chest clinicians should consider the impact of mood symptoms and comorbidity on the HRQOL in the management of patients with pneumoconiosis.  (+info)

Dust exposure and pneumoconiosis in a South African pottery. 1. Study objectives and dust exposure. (72/300)

Dust exposure and pneumoconiosis were investigated in a South African pottery that manufactured wall tiles and bathroom fittings. This paper describes the objectives of the investigation and presents dust measurement data. x Ray diffraction showed that the clays used by the pottery had a high quartz content (range 58%-23%, mean 38%). Exposure to respirable dust was measured for 43 workers and was highest (6.6 mg/m3) in a bathroom fitting fettler. Quartz concentrations in excess of 0.1 mg/m3 were found in all sections of the manufacturing process from slip production to biscuit firing and sorting. The proportion of quartz in the respirable dust of these sections was 24% to 33%. This is higher than is usually reported in English potteries. Four hundred and six (80%) of the 509 workers employed at the pottery were potentially at risk of occupational lung disease. The finding of large numbers of pottery workers exposed to unacceptable dust concentrations is not surprising as poor dust control was found in all six wall tile and sanitary ware factories surveyed by the National Centre for Occupational Health between 1973 and 1989. Dust related occupational disease can be expected in potters for many years to come.  (+info)